(1) Field of the Invention
The present invention is directed to passive acoustic arrays. In particular, the present invention is directed to a system and method for calculating the directivity index of a passive acoustic array with directional sensors in an isotropic noise field, and to provide an efficient way to create, modify, and model any array geometry for the purposes of determining the directivity index of the array as a function of array geometry, sensor geometry, sensor to sensor spacing, and number of sensors.
(2) Description of the Prior Art
Passive acoustic arrays are a necessary component of an underwater vehicle's sonar system. In order to better develop the technology of passive acoustic arrays, it is necessary to develop a system and method for calculating the directivity index of an acoustic array. There are several prior art methods that calculate the directivity index of an array of sensors. The inputs to these prior art methods include the geometry of the array, the number of sensors, shading coefficients for each sensor, sound speed of the operating medium, and the array steering. The prior art methods are limited to array geometries with simple shapes such as a line, plane, cylinder, or sphere, and capable of addressing arrays with point receiver sensors only. In addition, prior art methods calculate the directivity of each sensor within the array as frequency independent and limited to either an omni-directional or cosine function dipole response. What is needed is a system and method for calculating the directivity index of a passive acoustic array that can factor in complex sensor and array geometries and can provide a directivity index that is also frequency dependant and not limited to either an omni-directional or cosine function dipole response.